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Abrasion resistance: the ability to resist being worn away by contact with another moving, abrasive surface, such as foot traffic, mechanical equipment, wind-blown particles, etc.
Aluminum: a nonrusting, malleable metal
sometimes used for metal roofing and flashing.
Anodic: a metal or material that readily
gives up electrons to a cathodic material in the
presence of an electrolyte (see Galvanic series).
ANSI: American National Standards Institute.
Anticapillary hem: a hem used in a metal
panel seam to reduce the potential for water
migration.
APA: American Plywood Association.
APC: American Plastics Council.
APP: see Atactic polypropylene. Application rate: the average quantity (mass, volume or thickness) of material applied per unit area.
Apron flashing:
a term used for a flashing
located at the juncture of the top of a sloped roof
and a vertical wall, chimney or steeper-sloped roof.
APC/SPFA: American Plastics Council/Spray
Polyurethane Foam Alliance.
Architectural panel: a metal roof panel,
typically a double standing seam or batten seam;
usually requires solid decking underneath and relies
on slope to shed water.
Architectural shingle: an asphalt shingle
that provides a dimensional appearance.
Area divider: a raised, flashed assembly,
typically a single- or double-wood member attached
to a wood base plate, that is anchored to the roof
deck. It is used to accommodate thermal stresses in
a roof system where an expansion joint is not
required, or to separate large roof areas or
separate roof systems comprised of
different/incompatible materials, and may be used to
facilitate installation of tapered insulation.
ARMA: Asphalt Roofing Manufacturers
Association.
Area practices: design or application
techniques peculiar to a specific geographical
region.
Asbestos: a group of natural, fibrous, impure
silicate materials.
ASHRAE: American Society of Heating,
Refrigerating and Air-Conditioning Engineers. Asphalt: a dark brown or black substance found in a natural state or, more commonly, left as a residue after evaporating or otherwise processing crude oil or petroleum. Asphalt may be further refined to conform to various roofing grade specifications:
Asphalt, Air blown: asphalt produced by
blowing air through molten asphalt to raise its
softening point and modify other properties.
Asphalt emulsion: a mixture of asphalt
particles and emulsifying agent, such as bentonite
clay and water.
Asphalt felt: an asphalt-saturated and/or
asphalt-coated felt (see Felt).
Asphalt primer: See Primer.
Asphalt roof cement: a trowelable mixture of
solvent-based bitumen, mineral stabilizers, other
fibers and/or fillers. Classified by ASTM Standard D
2822-1 Asphalt Roof Cement, and D 4586-2 Asphalt
Roof Cement, Asbestos-Free, Types I and II.
Asphalt shingle: a shingle manufactured by
coating a reinforcing material (felt or fibrous
glass mat) with asphalt and having mineral granules
on the side exposed to the weather. (see Shingle)
Asphaltene: a high molecular weight
hydrocarbon fraction precipitated from asphalt by a
designated solvent (paraffinic naphtha) at a
specified temperature and solvent-asphalt ratio.
ASTM: American Society for Testing and
Materials.
Atactic polypropylene: a group of high
molecular weight polymers formed by the
polymerization of propylene.
Attic: the cavity or open space above the
ceiling and immediately under the roof deck of a
steep-sloped roof. Back-nailing (also referred to as “Blind-nailing”): the practice of blind nailing the back portion of a roofing ply, steep roofing unit, or other components in a manner so that the fasteners are covered by the next sequential ply, or course, and are not exposed to the weather in the finished roof system.
Ballast: a material, such as
aggregate or precast concrete payers, which employs
its mass and the force of gravity to hold (or assist
in holding) single-ply roof membranes in place.
Bar joist: (see Steel joist).
Barrel vault: a building profile featuring a
rounded profile to the roof on the short axis, but
with no angle change on a cut along the long axis.
Barrier board: noncombustible board stock
material of low thermal conductivity placed between
two elements of a roof assembly.
Base flashing (membrane base flashing): plies or
strips of roof membrane material used to close-off
and/or seal a Base ply: the bottom or first ply in a built-up roof membrane when additional plies are to be subsequently installed.
Base sheet:
an impregnated, saturated, or coated felt placed as
the first ply in some low-slope roof systems.
Batten: (1) cap or cover; (2) in a metal
roof, a metal closure set over, or covering the
joint between, adjacent metal panels; (3) in a wood
roof, a strip of wood usually set in or over the
structural deck, used to elevate and/or attach a
primary roof covering such as tile; (4) in a single
ply membrane roof system, a narrow plastic, wood or
metal bar that is used to fasten or hold the roof
membrane and/or base flashing in place.
Batten seam: a metal panel profile attached
to and formed around a beveled wood or metal batten.
Bentonite: a porous clay formed by the
decomposition of volcanic ash that swells 5 to 6
times its original volume in the presence of water.
Bermuda seam: a metal panel profile featuring a step-down profile that runs perpendicular to the slope of the roof.
Bird bath:
random, inconsequential amounts of residual water on
a roof membrane. Bitumen: (1) a class of amorphous, black or dark colored, (solid, semi-solid or viscous)
cementitious substances, natural or manufactured,
composed principally of high molecular weight
hydrocarbons, soluble in carbon disulfide, and found
in asphalts, tars, pitches and asphaltenes; (2) a
generic term used to denote any material composed
principally of bitumen, typically asphalt or coal
tar.
Bitumen-stop: see Envelope or Bleed-sheet.
Bituminous emulsion: a suspension of minute
particles of bituminous material in water.
Blackberry (also referred to as “Blueberry”
or “Tar-boil”): a small bubble or blister in the
flood coat of an aggregate-surfaced built-up roof
membrane.
Blanket (batt) insulation: glass fiber or other
compressible fibrous insulation, generally available
in roll form.
Bleed-sheet: a sheet material used to prevent
the migration of bitumen.
Bleeder strip: (see Rake-starter).
Blind-nailing: the use of nails that are not
exposed to the weather in the finished roofing
system.
Blister: an enclosed pocket of air, which may
be mixed with water or solvent vapor, trapped
between impermeable layers of felt or membrane, or
between the membrane and substrate.
Blocking: sections of wood (which may be
preservative treated) built into a roof assembly,
usually attached above the deck and below the
membrane or flashing, used to stiffen the deck
around an opening, act as a stop for insulation,
support a curb, or serve as a nailer for attachment
of the membrane and/or flashing.
Blowing agent: an expanding agent used to
produce a gas by chemical or thermal action, or
both, in manufacture of hollow or cellular
materials.
BOCA: Building Officials and Code
Administrators, International, Inc.
Bond: the adhesive and/or cohesive forces
holding two components in positive contact. Boot: (1) a covering made of flexible material, which may be preformed to a particular shape, used to exclude dust, dirt, moisture, etc., from around a penetration; (2) a flexible material used to form a closure, sometimes installed at inside and outside corners.
Brake: hand- or
power-activated machinery used to bend metal.
Bridging: (1) when membrane or base flashing
is unsupported at a juncture; (2) bridging in
steep-slope roofing occurs when reroofing over
standard-sized asphalt shingles with metric-sized
asphalt shingles.
British thermal unit (BTU): the heat energy
required to raise the temperature of 1 pound of
water degree Fahrenheit (joule). For the metric
equivalent, see Joule.
Broadcast: uniformly cast or distribute
granular or aggregate surfacing material.
Brooming: to improve the embedding of a ply
or membrane by using a broom or squeegee to smooth
it out and ensure contact with the adhesive under
the ply or membrane.
Buckle: an upward, elongated displacement of
a roof membrane frequently occurring over insulation
or deck joints. A buckle may be an indication of
movement within the roof assembly.
Building code: The minimum construction
requirements established generally by national
organizations of experts and adopted completely or
in altered form by local governing authorities.
Built-up roof (BUR): a continuous,
semi-flexible roof membrane, consisting of multiple
plies of saturated felts, coated felts, fabrics or
mats assembled in place with alternate layers of
bitumen, and surfaced with mineral aggregate,
bituminous materials, a liquid-applied coating or a
granule-surfaced cap sheet.
Bundle: an individual package of shakes or
shingles.
Bun stock: large solid box-like structure
formed during the production of polystyrene
insulation; individual board stock pieces are then
cut from the bun.
Butt joint: a joint formed by adjacent,
separate sections of material, such as where two
neighboring pieces of insulation abut.
Button punch: a process of indenting two or
more thicknesses of metal that are pressed against
each other to prevent slippage between the metal.
Butyl: rubber-like material produced by
polymerizing isobutylene.
Butyl coating: an elastomeric coating system
derived from polymerized isobutylene. Butyl coatings
are characterized by low water vapor permeability.
Butyl rubber: a synthetic elastomer based on
isobutylene and a minor amount of isoprene. It can
be vulcanized and features low permeability to gases
and water vapor.
Butyl tape: a sealant tape sometimes used
between metal roof panel seams and/or end laps; also
used to seal other types of sheet metal joints, and
in various sealant applications.
Calender: (1) to press between rollers or
plates in order to smooth and glaze or to thin into
sheets; (2) a machine for calendering.
Camber: a slight convexity, arching or
curvature (as of a beam, roof deck or road). Canopy: any overhanging or projecting roof structure, typically over entrances or doors.
Cant: in SPF-based roofing, a
beveling of foam at horizontal/vertical joints to
increase strength and promote water run off.
Cant strip: a beveled strip used under
flashings to modify the angle at the point where the
roofing or waterproofing membrane meets any vertical
element. Cap flashing: (1) usually composed of metal, used to cover or shield the upper edges of the membrane base flashing wall flashing; (2) a flashing used to cover the top of various buildings components, such as parapets or columns. (see Flashing and Coping.)
Cap sheet: a sheet,
often granule-surfaced, used as the top ply of some
built-up or modified bitumen roof membranes and/or
flashings.
Capacitance meter: a device used to locate
moisture or wet materials within a roof system by
measuring the ratio of the change to the potential
difference between two conducting elements separated
by a non-conductor.
Capillary action: (1) the action by which the
surface of a liquid where it is in contact with a
solid is elevated or depressed depending on the
relative attraction of the molecules of the liquid
for each other and for those of the solid; (2) the
siphoning of liquid into a joint or void between two
adjacent surfaces.
Catalyst: an ingredient that initiates a
chemical reaction or increases the rate of a
chemical reaction when combined with another
chemical.
Cathodic: A metal or material that readily
attracts electrons from an anodic material in the
presence of an electrolyte (see Galvanic Series).
Caulk: a composition of vehicle and pigment used
at ambient temperatures for filling/sealing joints
or junctures, that remains elastic for an extended
period of time after application.
Caulking: (1) the physical process of sealing
a joint or juncture; (2) sealing and making
weather-tight the joints, seams or voids between
adjacent surfaces by filling with a sealant.
Cavitation: the formation of a partial vacuum
or cavity in a liquid.
Cavity wall: an exterior wall usually of
masonry, consisting of an outer and inner withe
separated by a continuous air space, but connected
together by wire or sheet-metal tiles.
C-channel: a structural framing member.
Cellular glass insulation: A rigid
closed-cell insulation board made from crushed glass
and hydrogen sulfide gas.
Cementitious waterproofing: heavy
cement-based compounds and various additives that
are mixed and packaged for use in a dry form; the
packaged mixture is then mixed with water and liquid
bonding agents to a workable concrete-like
consistency.
Centipoise: a unit of measure of absolute
viscosity. (The viscosity of water is one centipoise.
The lower the number, the less viscous the
material.)
Centistoke: a unit of viscosity; the ratio of
a liquid’s absolute viscosity to the density of that
liquid.
CERL: Construction Engineering Research
Laboratory.
Chalk: a powdery residue on the surface of a
material. Chalk line: a line made on the roof or other flat surface by snapping a taut string or cord dusted with colored chalk.
Chalking:
the formation of a powdery surface
condition from the disintegration of a binder
or elastomer. Channel flashing: in steep-slope roof construction, a type of flashing used at roof-to-wall junctures and other roof- to-vertical plane intersections where an internal gutter is needed to handle runoff. Commonly used with profile tile.
Chemical resistance:
the ability to withstand contact with
specified chemicals without a significant change in
properties.
Chimney: stone, masonry, prefabricated metal
or wood-framed structure, containing one or more
flues, projecting through and above the roof.
Chlorinated polyethylene (CPE): a
thermoplastic material, used for single-ply roof
membranes, composed of high molecular weight
polyethylene that has been chlorinated with a
process that yields a flexible rubber-like material.
Chlorosulfonated polyethylene (CSPE or CSM): probably best known by the DuPont trade name Hypalon, a synthetic, rubber-like thermoset material, based on high molecular weight polyethylene with sulphonyl chloride, usually formulated to produce a self-vulcanizing membrane. Classified by ASTM Standard D 5019.
Cladding: a material used as
the exterior wall enclosure of a building.
Cleat: a continuous metal strip, or angled
piece, used to secure metal components (also see
Clip).
Clerestory: an upward extension of enclosed
space created by carrying a setback vertical, wall
(typically glazed) up and through the roof slope.
Two intersecting shed roofs on different planes.
Clip: a non-continuous metal component or
angle piece used to secure two or more metal
components together. (see Cleat.)
Clipped gable: a gable cutback near the peak
in a hip-roof form.
Closed-cut valley: a method of valley
application in which shingles from one side of the
valley extend across the valley while shingles from
the other side are trimmed back approximately 2
inches (51 mm) from the valley centerline.
Closure strip: a metal or resilient strip, such
as neoprene foam, used to close openings created by
joining metal panels or sheets and flashings.
Coal tar: a dark brown to black colored,
semi-solid hydrocarbon produced by the distillation
of coal. Coal tar pitch is further refined to
conform to the following roofing grade
specifications:
Coal tar pitch: a coal tar used as the
waterproofing agent in dead-level or low-slope
built-up roof membranes and membrane waterproofing
systems, conforming to ASTM Specification D 450,
Type I.
Coal tar waterproofing pitch: a coal tar used
as the dampproofing or waterproofing agent in
below-grade structures, conforming to ASTM
Specification D 450, Type II.
Coal tar bitumen: a proprietary trade name
for Type Ill coal tar used as the dampproofing or
waterproofing agent in dead-level or low-slope
built-up roof membranes and membrane waterproofing
systems, conforming to ASTM D 450, Type Ill.
Coal tar felt: a felt that has been saturated
or impregnated with refined coal tar.
Coal tar roof cement: a trowelable mixture of
processed coal tar base, solvents, mineral fillers
and/or fibers. Classified by ASTM Standard D 4022,
“Coal Tar Roof Cement, Asbestos Container.”
Coarse orange peel surface texture: a surface
showing a texture where nodules and valleys are
approximately the same size and shape. This surface
is acceptable for receiving a protective coating
because of the roundness of the nodules and valleys.
Coated base sheet: a coated felt intended to
be used as a base ply in a built-up or modified
bitumen roof membrane.
Coated fabric: fabrics that have been
impregnated and/or coated with a plastic like
material in the form of a solution, dispersion
hot-melt or powder. The term also applies to
materials resulting from the application of a
preformed film to a fabric by means of calendering.
Coated felt (Sheet): (1) an asphalt felt that
has been coated on both sides with harder, more
viscous asphalt; (2) a glass fiber felt that has
been simultaneously impregnated and coated with
asphalt on both sides.
Coating: a layer of liquid material applied
to a surface for protection or appearance.
Cobwebbing: a phenomenon observed during
spray application characterized by the formation of
web-like threads along with the usual droplets
leaving the spray gun nozzle.
Code: a collection of laws (regulations,
ordinances or statutory requirements) adopted by
governmental authority. (see Building code and Model
code.)
Coefficient of thermal expansion: the
coefficient of change in dimension of a material per
unit of dimension per degree change in temperature.
Cohesion: the molecular forces of attraction
by which the body of a material is held together.
Coil coating: the application of a finish to
a coil of metal using a continuous mechanical
coating process.
Cold forming: the process of shaping metal
into desired profiles without the application of
heat.
Cold rolled: the process of forming steel
into sheets, panels, or shapes on a series of
rollers at room temperature.
Cold roof assembly: a roof assembly
configured with the insulation below the deck, not
typically in contact with the deck, allowing for a
ventilation space. The temperature of the roof
assembly remains close to the outside air
temperature.
Color stability: the ability of a material to
retain its original color after exposure to weather.
Column: in structures, a relatively long,
slender structural compression member such as a
post, pillar or strut; usually vertical which acts
in (or near) the direction of its longitudinal axis.
Combing ridge: a term used to describe an
installation of finishing slate or wood at the ridge
of a roof whereby the slates on one side project
beyond to the apex of the ridge.
Combustible: capable of burning.
Combustion: a chemical process of oxidation
that occurs at a rate fast enough to produce heat
and usually light either as glow or flames; the
process of burning.
Compatible materials: two or more substances
that can be mixed, blended, or attached without
separating, reacting, or affecting the materials
adversely.
Composition shingle: a unit of asphalt
shingle roofing.
Composite board roof insulation: rigid board
insulation generally comprised of perlite or wood
fiberboard factory bonded to polyisocyanurate or
polystyrene.
Compounded thermoplastics: a category of
roofing membranes made by blending thermoplastic
resins with plasticizers, various modifiers,
stabilizers, flame retardants, UV absorbers,
fungicides and other proprietary substances alloyed
with proprietary organic polymers.
Compressive strength: the property of a
material that relates to its ability to resist
compression loads.
Concealed-nail method: a method roofing
application in which all nails are driven into the
underlying course of roofing and covered by a
subsequent, overlapping course.
Concealed plate: see Cover plate.
Condense: to make denser or more compact, as
when a material (e.g. water vapor) changes from its
gas phase to its liquid phase.
Condensate: the liquid resulting from the
condensation of a gas.
Condensation: the conversion of water vapor
or other gas to liquid phase as the temperature
drops; the act or process of condensing.
Conditioning: the storage of a material
specimen under specified temperature, humidity, etc.
for a specified time prior to testing.
Conductance, Thermal: the thermal
transmission in unit time through unit area of a
particular body or assembly having defined surfaces,
when unit average temperature difference is
established between the surfaces. C=Btu/hft2̊F
(C=W/m2.K).
Conductor head: an enlargement or catch basin
at the top of a downspout or leader to receive
rainwater from a gutter or scupper.
Construction joint: (1) a joint where two
successive placements of concrete meet; (2) a
separation provided in a building which allows its
component parts to move with respect to each other.
Contact cements: adhesives used to adhere or
bond various roofing components. These adhesives
adhere mated components immediately on contact of
surfaces to which the adhesive has been applied.
Contamination: the process of making a
material or surface unclean or unsuited for its
intended purpose, usually by the addition or
attachment of undesirable foreign substances.
Control joint: a groove which is formed,
sawed, or tooled in a concrete or masonry structure
to regulate the location and amount of cracking and
separation resulting from the dimensional change of
different parts of the structure, thereby avoiding
the development of high stresses.
Coping: the covering piece on top of a wall
exposed to the weather, usually made of metal,
masonry, or stone and sloped to carry off water.
Copolymer: the product of polymerization of
two or more substances (as two different isomers)
together.
Copolymerization: a chemical reaction that
results in the bonding of two or more dissimilar
monomers to produce large, long-chain molecules that
are copolymers.
Copper: a natural weathering metal used in
metal roofing or flashing; typically used in 16
ounce per square foot (0.56 mm) and 20 ounce per
square foot (0.69 mm) thicknesses.
Core cut or core sample: (1) a sample from a
low-slope roof system taken for the purpose of
obtaining primarily qualitative information about
its construction. Typically, core cut analysis can
verify or reveal the type of membrane surfacing; the
type of membrane; the approximate number of plies;
the type, thickness and condition of the insulation
(if any); and the type of deck used as a substrate
for the roof system. (2) for in SPF-based roof
systems, core cuts are used to obtain both
quantitative and qualitative information, such as
the thickness of the foam, the thickness and
adhesion of the coating, thickness of individual
passes and adhesion between passes and the adhesion
of the foam to its substrate.
Cornice: the decorative horizontal molding or
projected roof overhang.
Counter batten: vertical wood strips
installed on sloped roofs over which horizontal
battens are secured. The primary roof covering is
attached or secured to these horizontal battens.
Counterfiashing: formed metal or elastomeric
sheeting secured on or into a wall, curb, pipe,
rooftop unit or other surface, to cover and protect
the upper edge of a base flashing and its associated
fasteners.
Course: (1) the term used for a row of
roofing material that forms the roofing,
waterproofing or flashing system; (2) one layer of a
series of materials applied to a surface (e.g., a
five-course wall flashing is composed of three
applications of roof cement with one ply of felt or
fabric sandwiched between two layers of roof
cement).
Cover board: an insulation board used over
closed cell plastic foam insulation (e.g.,
polyisocyanurate) to prevent blistering when used in
conjunction with hot bituminous membranes. Suitable
cover board insulation are glass- faced siliconized
gypsum board, glass-fiber board, perlite board,
wood-fiber board or mineral-fiber board. Cover
boards are also recommended between polyisocyanurate
insulation and single ply membranes to protect the
polyisocyanurate.
Cover plate: a metal strip sometimes
installed over or under the joint between formed
metal pieces.
Coverage: the surface area uniformly covered
by a specific quantity of a particular material at a
specific thickness.
CPA: copolymer alloy.
Crack: a nonlinear separation or fracture
occurring in a material.
Cream time: time in seconds (at a given
temperature) when the A and B components of
polyurethane foam will begin to expand after being
mixed. Recognizable as a change in color of the
materials.
Cricket: a relatively small area of a roof
constructed to divert water from a horizontal
intersection of the roof with a chimney, wall,
expansion joint or other projection. (see Saddle.)
Cross-linking: the formation of chemical
bonds between polymeric chains. Cross-linking of
rubber is referred to as vulcanization or “curing.”
CRREL: Cold Regions Research and Engineering
Laboratory.
Crystalline waterproofing: a compound of
cement, quartz or silica sand, and other active
chemicals that are mixed and packaged for use in a
dry powder form; the packaged mixture is then mixed
with water and applied to a concrete surface where
it penetrates into the pores of concrete.
CSPE: chlorosulfonated polyethylene.
Cupola: a relatively small roofed structure,
generally set on the ridge or peak of a main roof
area for ventilation or aesthetic purposes.
Curb: (1) a raised member used to support
roof penetrations, such as skylights, mechanical
equipment, hatches, etc. above the level of the roof
surface; (2) a raised roof perimeter relatively low
in height.
Cure: a process whereby a material is caused
to form permanent molecular linkages by exposure to
chemicals, heat, pressure and/or weathering. Cure time: the time required for a material to reach its desirable long-term physical characteristics.
Cured concrete:
concrete that has attained its
intended design performance properties.
Curing agent: an additive in a coating or
adhesive that results in increased chemical activity
between the components with an increase or decrease
in rate of cure.
Curing compound: a liquid that is sprayed or
otherwise applied to newly placed concrete which
retards the loss of water during curing.
Cutback: solvent-thinned bitumen used in
cold-process roofing adhesives, roof cements and
roof coatings.
Cutoff: a permanent detail designed to prevent
lateral water movement in an insulation system and
used to isolate
Cutout: the open portions of a strip shingle
between the tabs. Sometimes referred to as a keyway.
Dampproofing: treatment of a surface or
structure to resist the passage of water in the
absence of hydrostatic pressure.
Dead level: absolutely horizontal or zero
slope. (see Slope.)
Dead-level asphalt: see Asphalt.
Dead loads: the weight of a structure itself,
including the weight of fixtures or equipment
permanently attached to it.
Deck: a structural component of the roof of a
building. The deck must be capable of safely
supporting the design dead and live loads, including
the weight of the roof systems, and the additional
live loads required by the governing building codes
and provide the substrate to which the roofing or
waterproofing system is applied the structural
surface of a building to which a roof assembly is
installed. Decks are either non-combustible (e.g.,
corrugated metal, concrete, or gypsum) or
combustible (e.g., wood plank or plywood).
Deflection (bowing, sagging): (1) the
deformation of a structural member as a result of
loads acting on it; (2) any displacement in a body
from its static position, or from an established
direction or plane, as a result of forces acting on
the body.
Degradation: a deleterious change in the
chemical structure, physical properties or
appearance of a material from natural or artificial
exposure (e.g., exposure to radiation, moisture,
heat, freezing, wind, ozone, oxygen, etc.).
Degree days: a unit used in estimating the
fuel consumption for a building; equal to the number
of degrees that the mean temperature, for a 24-hour
day, is below the “base temperature”; the base
temperature is taken as 65̊ F (18.3̊ C) in the
U.S.A.
Delamination: separation of the laminated
layers of a component or system.
Design loads: the total load on a structural
system for the most severe combination of loads and
forces which it is designed to sustain.
Dew-point temperature: the temperature at
which air becomes saturated with water vapor. The
temperature at which air has a relative humidity of
100%.
Diaphragm: a floor slab, metal wall panel,
roof panel, or the like, having a sufficiently large
in-plane shear stiffness and sufficient strength to
transmit horizontal forces to resisting systems.
Diffusion: the movement of water vapor from
regions of high concentration (high water vapor
pressure) toward regions of lower concentration.
Dimensional shingle: a shingle that is
textured, overlayed, or laminated and designed to
produce a three-dimensional effect. (also see
Laminated shingle and Architectural shingle.)
Dimensional stability: the degree to which a
material maintains its original dimensions when
subjected to changes in temperature and humidity.
DOE: U.S. Department of Energy.
Dormer: a structure projecting from a sloping
roof usually housing a window or ventilating louver.
Double coverage: application of asphalt,
slate, or wood roofing such that the lapped portion
is at least 2 inches
Double lock standing seam: in a metal roof
panel or metal cap, a standing seam that uses a
double overlapping
Double pour: to apply two layers or flood
coats of bitumen and aggregate to a built-up roof.
Downspout: a vertical pipe or conduit used to
carry runoff water from a scupper, conductor head or
gutter of a building to a lower roof level or to the
ground or storm water runoff system.
Drag load: the external force (e.g. from the
weight of ice and snow) applied to a steep-slope
roof system component forcing the component
downslope.
Drain: an outlet or other device used to
collect and direct the flow of runoff water from a
roof area.
Drip edge: a metal flashing or other
overhanging component with an outward projecting
lower edge, intended to control the direction of
dripping water and help protect underlying building
components.
Dry: free or relatively free from a liquid,
especially water; (2) to remove water or moisture.
Dry bulb temperature: the temperature of air as
measured by an ordinary thermometer.
Dry film thickness: the thickness, expressed
in mils, of an applied and cured coating or mastic.
For comparison, see Wet film thickness.
Drying time: the time required for the loss
of volatile components so that the material will no
longer be adversely affected by weather conditions
such as dew, rain, or freezing.
Dual level drain: in waterproofing, an outlet
or other device with provisions for drainage at both
the wearing surface and waterproofing membrane
levels used to collect and direct the flow of runoff
water from a horizontal slab.
Dynamic load: any load which is nonstatic,
such as a wind load or moving live load.
Eave:
the lower edge of a sloping roof that part of a roof
which projects beyond the wall.
Eave height: the vertical dimension from
finished grade to the eave.
Eave-trough: see Gutter.
ECH: polyepichlorohydrin, commonly referred
to as epichlorohydrin. (see Epichlorohydrin.)
Edge stripping: membrane flashing strips cut
to specific widths used to seal/flash perimeter edge
metal and the roof membrane application of felt
strips cut to narrower widths than the normal
felt-roll width to cover a joint between metal
perimeter flashing and built-up roofing. Edge venting: the practice of providing regularly spaced or continuously protected (e.g., louvered) openings along a roof edge or perimeter, used as part of a ventilation system to dissipate heat and moisture vapor.
Efflorescence: an encrustation
of soluble salts, commonly white, deposited on the
surface of stone, brick, plaster, or mortar; usually
caused by free alkalies leached from mortar or
adjacent concrete as moisture moves through it.
EIP: ethylene interpolymer.
Elasticity: the property of a body that
causes it to tend to return to its original shape
after deformation (as stretching, compression or
torsion).
Elastomer: a macromolecular material that
returns rapidly to its approximate initial
dimensions and shape after substantial deformation
by a weak stress and subsequent release of that
stress.
Elastomeric coating: a coating that is
capable of being stretched at least twice its
original length (100 percent elongation) and
recovering to its original dimensions.
Elongation: the ratio of the extension of a
material to the length of the material prior to
stretching.
Embedment: (1) the process of
pressing/positioning a felt, aggregate, fabric, mat,
or panel into hot bitumen or adhesive to ensure
intimate contact at all points; (2) the process of
pressing/positioning granules into coating in the
manufacture of factory-prepared roofing, such as
shingles.
Embrittlement: the loss of flexibility or
elasticity of a material.
Emulsion: A mixture of bitumen and water,
with uniform dispersion of the bitumen or water
globules, usually stabilized by an emulsifying agent
or system.
End lap: the distance of overlap where one
ply, pane, or piece extends beyond the end of the
immediately adjacent underlying ply, panel, or
piece.
Envelope (Bitumen-stop): a continuous
membrane edge seal formed at the perimeter and at
penetrations by folding the base sheet or ply over
the plies above and securing it to the top of the
membrane. The envelope prevents bitumen seepage from
the edge of the membrane.
EPDM: Ethylene propylene diene monomer (see
also Ethylene propylene diene terpolymer.)
Epichlorohydrin (ECH): a synthetic rubber
including two epichlorohydrin based elastomers. It
is similar to and compatible with EPDM.
Epoxy: a class of synthetic, thermosetting
resins that produce tough, hard, chemical-resistant
coatings and adhesives.
Equilibrium moisture content (EMC):
(1) the
moisture content of a material stabilized at a given
temperature and relative humidity, expressed as
percent moisture by weight.
Equiviscous temperature (EVT): the
temperature at which a bitumen attains the proper
viscosity for built-up membrane application.
Equiviscous temperature (EVT)
application
range: the recommended bitumen application
temperature range. Equiviscous temperature (EVT) for asphalt: the recommended EVTfor roofing asphalt (ASTM D 312, Type I, II, III or IV) is as follows:
Equiviscous temperature (EVT)
for coal tar: the recommended EVT
for roofing coal tar (ASTM D 450, Type I or lii) is
the temperature at which the coal tar’s apparent
viscosity is 25 centipoise (0.025 Pa.s).
Ethylene interpolymers (EIP): a group of
thermoplastic compounds generally based on PVC
polymers from which certain single-ply roofing
membranes can be formulated.
Ethylene propylene diene terpolymer (EPDM):
designated nomenclature of ASTM for a terpolymer of
ethylene, propylene and diene. EPDM material is a
thermosetting synthetic elastomer.
EVT: Equiviscous temperature.
Exhaust ventilation: air that is vented or
exhausted from the roof cavity, typically through
vents installed on the up slope portion of the roof.
For example, with most steep-slope roof assemblies,
exhaust vents are typically located at or near the
ridge.
Exotherm: heat generated by a chemical
reaction.
Expansion cleat: a cleat designed to
accommodate thermal movement of metal roof panels.
Expansion joint: a structural separation
between two building elements that allows free
movement between the elements without damage to the
roofing or waterproofing system.
Exposed-nail method: a method of asphalt roll
roofing application in which all nails are driven
into the adhered, overlapping course of roofing.
Nails are exposed to the weather.
Exposure: (1) the traverse dimension of a
roofing element or component not overlapped by an
adjacent element or component in a roof covering.
For example, the exposure of any ply in a built-up
roof membrane may be computed by dividing the felt
width, minus 2 inches (51 mm), by the number of
shingled plies; thus, the exposure of 36 inch (914
mm) wide felt in a shingled, four-ply membrane
should be approximately 8Y inches (216 mm) (See
Figure 8); (2) the dimension of sidewall or roofing
covering that is not covered or overlapped by the up
slope course of component. The typical exposure for
a standard-sized, three-tab shingle is 5 inches (127
mm), depending on manufacturer specifications.
Extrusion: a process in which heated or
unheated material is forced through a shaping
orifice (a die) in one continuously formed shape, as
in film, sheet, rod or tubing.
Eyebrow: a dormer, usually of small size,
whose roof line over the upright face is typically
an arched curve, turning into a reverse curve to
meet the horizontal at either end. Also, a small
shed roof projecting from the gable end of the
larger, main roof area.
Fabric: a woven cloth or material of organic
or inorganic filaments, threads, or yarns used for
reinforcement in certain membranes and flashings.
Factory Mutual Research (FMR): commonly
referred to as “FM,” a research and testing
organization that classifies roofing components and
assemblies for their fire, traffic, impact (hail),
weathering, and wind-uplift resistance for four
major insurance companies in the United States.
Factory seam: a splice/seam made by the
manufacturer during the assembly of sections of
materials into larger sheets/panels.
Fading: any lightening of initial color.
Fallback: a reduction in bitumen softening
point, sometimes caused by refluxing or overheating
in a relatively closed container. (see Softening
Point Drift.)
Fascia: (1) in steep-slope roofing, a board
that is nailed to the ends of a roof rafter;
sometimes supports a gutter; (2) in low-slope
roofing, the vertical or steeply sloped roof or trim
located at the perimeter of a building. Typically,
it is a border for the low-slope roof system.
Fastener: any of a wide variety of mechanical
securement devices and assemblies, including nails,
staples, screws, cleats, clips and bolts, which may
be used to secure various components of a roof
assembly.
Feathering strips: tapered wood filler strips
placed along the butt ends of old wood shingles to
create a relatively smooth surface when reroofing
over existing wood shingle roofs. Referred to in
some regions of the country as “horse feathers,” or
leveling strips. Felt: a flexible sheet manufactured by the interlocking of fibers with a binder or through
a
combination of mechanical work, moisture and heat.
Felts are manufactured principally from wood pulp
and vegetable fibers (organic felts), asbestos
fibers (asbestos felts), glass fibers (glass fiber
felts or ply sheets), or polyester fibers.
Felt machine (Felt Layer): a mechanical
device used for applying bitumen and roofing felt or
ply sheet simultaneously.
Ferrule: a metal sleeve placed inside a
gutter at the top. A spike or screw is
nailed/screwed through the gutter face and ferrule
into the fascia board to hold the gutter in place.
The ferrule acts as a spacer in the gutter to
maintain its original shape.
Field seam: a splice or seam made in the field
(not factory) where overlapping sheets are joined
together using an adhesive, splicing tape, or heat-
or solvent-welding.
Filler: a relatively inert ingredient added
to modify physical characteristics.
Fillet: a heavy bead of waterproofing
compound or sealant material generally installed at
the point where vertical and horizontal surfaces
meet; to reduce the desired effect to take out the
90̊ angle at the base of a vertical flashing.
Film: sheeting having a nominal thickness not
greater than 10 mils (0.25 mm).
Film thickness: the thickness of a membrane
or coating. Wet film thickness is the thickness of a
coating as applied; dry film thickness is the
thickness after curing. Film thickness is usually
expressed in mils (thousandths of an inch).
Fin: a term used to describe a deck surface
condition. A sharp raised edge (generally in
concrete) capable of damaging a roof membrane or
vapor retarder.
Fine mineral-surfacing: water-insoluble,
inorganic material, more than 50 percent of which
passes through a No. 35 sieve. Used on the surface
of various roofing materials and membranes to
prevent sticking.
Fire resistance: the property of a material
or assembly to withstand fire or give protection
from it.
Fire retardant treated (FRT) plywood: plywood
which has been impregnated, under pressure, with
mineral salts; in the event of fire, the burning
wood and salts emit noncombustible gases and water
vapor instead of the usual flammable vapors.
Fishmouth: (also referred to as an edge
wrinkle) (1) a half-cylindrical or half-conical
shaped opening or void in a lapped edge or seam,
usually caused by wrinkling or shifting of ply
sheets during installation; (2) in shingles, a half-
conical opening formed at a cut edge.
Flaking: in protective coatings, the
detachment of small pieces of the coating film.
Flammable: subject to easy ignition and rapid
flaming combustion.
Flame retardant: a chemical used to impart
flame resistance.
Flame spread: the propagation of a flame away
from its source of ignition.
Flammability: those characteristics of a
material that pertain to its relative ease of
ignition and ability to sustain combustion. Flange: the projecting edge of a rigid or semi-rigid component, such as a metal edge flashing flange.
Flash point:
the lowest temperature at which vapors above a
volatile combustible substance ignite in air when
exposed to a flame.
Flashing: components used to weatherproof or
seal roof system edges at perimeters, penetrations,
walls, expansion joints, valley, drains and other
places where the roof covering is interrupted or
terminated. For example, membrane base flashing
covers the edge of the field membrane, and cap
flashings or counterflashings shield the upper edges
of the base flashing.
Flashing cement: a trowelable mixture of
solvent-based bitumen and mineral stabilizers that
may include asbestos or other inorganic or organic
fibers. Generally, flashing cement is characterized
as vertical-grade, which indicates it is intended
for use on vertical surfaces. (see Asphalt Roof
Cement and Plastic Cement.)
Flashing collar: (sometimes referred to as a
roof jack or flashing boot) an accessory flashing
used to cover and/or seal soil pipe vents and other
penetrations through the roof.
Flat lock: a method of interlocking metal
panels in which one panel edge is folded back on top
of itself and the other panel is folded under, after
which the two panels are hooked together.
Fleece: mats or felts composed of fibers,
sometimes used as a membrane backer.
Flood (pour) coat: the surfacing layer of
bitumen into which surfacing aggregate is embedded
on an aggregate- surfaced built-up roof.
Flood test: the procedure in which a
controlled amount of water is temporarily retained
over a horizontal surface to determine the
effectiveness of the waterproofing system.
Fluid-applied elastomer: a liquid elastomeric
material that cures after application to form a
continuous waterproofing membrane.
Fly-in: method of application for roll
materials by which the dry sheet is set into the
bitumen or adhesive applied to the roof surface.
FM: see Factory Mutual Research (FMR).
Foam stop: the roof edge treatment upon which
SPF is terminated.
Force: a strength or energy exerted or
brought to bear; cause of motion or change.
FPL: Forest Products Laboratory.
Froth pack: a term used to describe small,
disposable aerosol cans that contain SPF components.
Two component froth packs are available to do small
repairs for sprayed polyurethane foam-based roofs.
G-90: a designation for galvanized metal
sheet, indicating 0.90 ounces (26 g) of zinc per
square foot, measured on both sides.
Gable: the vertical triangular portion of the
end of a building having a double-sloping roof, from
the level of the eaves to the ridge of the roof.
Gable roof: a single-ridge roof that
terminates at gable end(s).
Galvalume: trade name for a metal alloy
coating that is composed of aluminum, zinc and
silicone.
Galvanic action: an electrochemical action
that generates electrical current between two metals
of dissimilar electrode potential.
Galvanic series: a list of metals and alloys
arranged according to their relative electrolytic
potentials in a given environment.
Galvanize: to coat steel or iron with zinc.
Galvanized steel: steel coated with zinc for
corrosion resistance.
Gambrel: a roof that has two pitches on each
side, where the upper roof area has less slope than
the lower roof areas.
Gauge: a metal thickness measurement.
Geocomposite: a prefabricated water drainage
material used to relieve hydrostatic pressure
against waterproofing and promote drainage.
Geotextile: a tightly woven fabric used to
restrict the flow of fine soil particles and other
contaminants while allowing water to pass freely
through; used to protect drainage systems from
clogging.
Girt: a horizontal beam that supports wall
cladding between columns.
Glass fiber insulation: blanket or rigid
board insulation, composed of glass fibers bound
together with a binder, faced or unfaced, used to
insulate roofs and walls.
Glass felt: glass fibers bonded into a sheet
with resin and suitable for impregnation with
asphalt in the manufacture of bituminous
waterproofing, roofing membranes and shingles.
Glass mat: a thin mat of glass fibers with or
without a binder.
Glaze coat: (1) the top layer of asphalt on a
smooth-surfaced built-up roof membrane; (2) a thin
protective coating of bitumen applied to the lower
plies or top ply of a built-up roof membrane when
application of additional felts or the flood coat
and aggregate surfacing are delayed. (also see Flood
coat.)
Gloss: the shine, sheen or luster of a dried
film.
Grain: a unit of measure in the English
System of units; 7,000 grains equals 1 lb.; used as
a measure of the weight of moisture in air.
Granule: (also referred to as mineral or
ceramic granule) opaque, natural or synthetically
colored aggregate commonly used to surface cap
sheets, shingles, and other granule-surfaced roof
coverings.
Gravel: coarse granular aggregate resulting
from the natural erosion of rock.
Gravel stop: a flanged device, frequently
metallic, designed to prevent loose aggregate from
washing off the roof and to provide a continuous
finished edge for the roofing.
Groundwater level: at a particular site, the
level, below which the subsoil and rock masses of
the earth are fully saturated with water.
Grout: a mixture of cement, sand, and water
used to fill cracks and cavities in masonry.
Gusset: used at the bottom of a steep-slope
roof system valley, a large flat metal piece(s)
wider than the valley to help prevent build-up at
the base of the valley, either from debris or ice
dam formations.
Gutter: a channeled component installed along
the downslope perimeter of a roof to convey runoff
water from the roof to the drain leaders or
downspouts.
Gypsum board panels: cementitious board stock
with noncombustible core primarily comprised of
gypsum that is commonly used as a barrier board
thermal barrier or cover board in a roof assembly.
Hand-tabbing: method of spot applying
asphalt-based adhesive to shingles for securement
and wind resistance.
Headlap: the distance of overlap measured
from the uppermost ply or course to the point where
it laps over the undermost ply or course.
Heat flow: the quantity of heat transferred
to or from a system in a unit of time.
Heat seaming: the process of joining
thermoplastic films, membranes, or sheets by heating
and then applying pressure to bring both materials
in contact with each other. (see Heat welding.)
Heat transfer: the transmission of thermal
energy from a location of higher temperature to a
location of lower temperature. This can occur by
conduction, convection or radiation.
Heat welding: method of melting and fusing
together the overlapping edges of separate sheets or
sections of polymer modified bitumen, thermoplastics
or some uncured thermoset roofing membranes by the
application of heat (in the form of hot air or open
flame) and pressure. (see Heat seaming.)
Hem: the edge created by folding metal back
on itself.
Hip: the inclined external angle formed by
the intersection of two sloping roof planes.
Hip roof: a roof that rises by inclined
planes to form one or more hips.
Hoist: a mechanical lifting device.
Holiday: an area where a liquid-applied
material is missing or absent.
Honeycomb: voids left in concrete resulting
from failure of the mortar to effectively fill the
spaces among coarse aggregate particles.
Hot or Hot stuff: a roofing worker’s term for
hot bitumen.
Hue: the subjective perception of color such
as red, yellow, green, blue, purple or some
combination; white, black or gray possess no hue.
Humidity: the condition of the atmosphere
with respect to water vapor. See relative humidity.
HVAC: heating, ventilating, and air conditioning equipment.
Hybrid roof covering:
combination of two or more separate and distinct
roof membranes; e.g., three ply smooth BUR and a
modified bitumen cap.
Hydration: the chemical reaction by which a
substance (such as Portland cement) combines with
water, giving off heat to form a crystalline
structure in its setting and hardening.
Hydrocarbon: an organic chemical compound
primarily containing the elements carbon and
hydrogen.
Hydrostatic pressure: the pressure equivalent
to that exerted on a surface by a column of water of
a given height.
Hydrostatic pressure relief system: a system
of perimeter and/or under slab drains used to
regulate the hydrostatic pressure in the earth
surrounding a below-grade structure.
Hygroscopic: attracting, absorbing and
retaining atmospheric moisture.
Hypalon: a registered trademark of E.l. du
Pont de Nemours & Co., for “chlorosulfonated
polyethylene” (CSPE). (see Chlorosulfonated
polyethylene.)
ICBO: International Conference of Building
Officials.
Ice dam: a mass of ice formed at the
transition from a warm to a cold roof surface,
frequently formed by refreezing meltwater at the
overhang of a steep roof, causing ice and water to
back up under roofing materials.
Ice dam protection membrane: a continuous
membrane installed under steep slope roofing
materials in areas subject to ice damming that
prohibits water which gets through the roof covering
from getting into the structure. Must also seal the
fasteners that penetrates it.
Ignition temperature: the lowest temperature
at which combustion will occur spontaneously under
specific conditions.
Impact resistance: resistance to fracture
under the sudden application of an exerted force.
Impregnate: In roofing materials manufacture,
to completely surround the fibers in a felt or mat
with bitumen, with the spaces between the fibers
partially or completely filled without a continuous
coating of bitumen on the surface.
Infrared thermography: The process of
displaying variations of apparent temperatures
(variation of temperature or emissivity or both)
over the surface of an object by measuring
variations in infrared radiance.
Inorganic: being or composed of materials
other than hydrocarbons and their derivatives, or
matter that is not of plant or animal origin.
Insect screen: wire mesh used to prevent
insects from entering the building through
ventilators, louvers, or other openings.
In-service R-value: thermal resistance value
established under installed conditions and measured
over the expected service life of the material.
Insulation: any of a variety of materials
designed to reduce the flow of heat, either from or
into a building. (see also Thermal insulation.)
Intake ventilation: the fresh air that is
drawn into a passive ventilation system through
vents typically installed in the soffit or eave of a
roof.
Interlayment: a felt, metal, or membrane
sheet material used between courses of steep-slope
roofing to improve the weather- and water-shedding
characteristics of the primary roof covering during
times of wind-driven precipitation. Typically used
with wood shakes.
Interlocking shingles: individual shingles
that mechanically attach to each other to provide
enhanced wind resistance without reliance on sealing
strips.
Inverted roof membrane assembly (IRMA]: a
patented, proprietary variation of the “protected
membrane roof assembly” in which Styrofoam brand
insulation and ballast are placed over the roof
membrane. IRMATM and Styrofoams are registered
trademarks of the Dow Chemical Company.
ISANTA: International Staple, Nail & Tool
Association
Isocyanate: a highly reactive organic
chemical containing one or more isocyanate (-N=C=0)
groups. A basic component in SPF based systems and
some polyurethane coating systems.
Isolation sheet: refer to slip sheet.
Joist: any of the small timbers, metal or
wood beams arranged parallel to each other and
spanning from wall to wall to support a floor,
ceiling, or roof of a building.
Joule: a unit of energy or work; equals the
work done by a force of 1 newton which acts over a
distance of 1 meter in the direction of the force.
k or k-Value:
thermal conductivity; the time rate
of heat flow through a unit area of a homogeneous
material in a direction perpendicular to isothermal
planes induced by a unit temperature gradient. In
English (inch-pound) units of measurement, it is the
number of BTUS that pass through a 1 inch (25 mm)
thickness of a 1 square foot (0.09 m2) sample of
material in 1 hour with a temperature difference
between the two surfaces of 10 F. It is expressed as
Btuinch/hft2̊F.
Kert: (1) a slit or notch made by a saw or
cutting torch; (2) the width of cut made by a saw or
cutting torch.
Kesternich test: simulates acid rain
conditions by subjecting test specimens to a sulfur
dioxide atmosphere as well as condensing moisture
for the purpose of evaluating rust/corrosion
characteristics.
Knee cap: a metal cover trim that fits over a
panel rib after it has been cut and bent.
Knee joints: see Knuckle.
Knuckle: a metal closure, either shop-or
pre-fabricated, installed over the cut seam of a
continuous metal roof panel at the transition from a
steep-slope roof to a vertical roof or wall.
Laitance: a weak layer of cement and
aggregate fines on a concrete surface that is
usually caused by an overwet mixture, overworking
the mixture, improper or excessive finishing or
combination thereof.
Laminate: to join layers of materials
together using fusion; the process of joining layers
of materials together using adhesion.
Laminated shingles: see Dimensional shingles
or Architectural shingles.
Lap: that part of a roofing, waterproofing,
or flashing component that overlaps or covers any
portion of the same or another type of adjacent
component.
Lap cement: an asphalt-based roof cement
formulated to adhere overlapping plies or asphalt
roll roofing.
Lap seam: occurs where overlapping materials
are seamed, sealed or otherwise bonded.
Latex: a stable dispersion of polymeric
substance in an essentially aqueous medium.
Lead: a soft malleable, heavy metal; has low
melting point and a high coefficient of thermal
expansion.
Leader head: see Conductor head.
Lift: the sprayed polyurethane foam that
results from a pass. It usually is associated with a
certain pass thickness and has a bottom layer,
center mass and top skin in its makeup.
Liquid-applied: application of bituminous
cements, adhesives or coatings installed at ambient
or slightly elevated temperatures.
Liquid-applied built-up roof: a continuous,
semi-flexible roof membrane, consisting of multiple
plies of felts, mats or fabrics laminated together
with alternate layers of roof cements and surfaced
with a liquid -applied coating with or without
aggregate surfacing.
Live loads: temporary loads that the roof
structure must be designed to support, as required
by governing building codes. Live loads are
generally moving and/or dynamic or environmental,
(e.g., people, installation equipment, snow, ice or
rain, etc.).
Loose-laid membrane: a ballasted roofing
membrane that is attached to the substrate only at
the edges and penetrations through the roof. Low-slope roofs: a category of roofs that generally include weatherproof membrane types of roof systems installed on slopes at or less than 3:12 (14 degrees).
Low temperature flexibility:
the ability of a membrane or other material to
resist cracking when flexed after it has been cooled
to a low temperature.
Mansard: a decorative steep-sloped roof on
the perimeter of a building.
Mansard roof: a steeper roof that terminates
into a flat roof at its high point.
Masonry: construction, usually set in mortar,
of natural building stone or manufactured units,
such as brick, concrete block, adobe, glass block,
tile, manufactured stone or gypsum block.
Mastic: a thick adhesive material used as a
cementing agent for holding waterproofing membrane
in place. (see Asphalt roof cement). Mat: a thin layer of woven, non-woven, or knitted fiber that serves as reinforcement to a material or membrane.
Mat slab:
a concrete slab designed with
reinforcement to resist the uplift forces created by
hydrostatic pressure.
Material safety data sheets (MSDS): a written
description of the chemicals in a product and other
pertinent data, including such things as safe
handling and emergency procedures. In accordance
with OSHA regulations, it is the manufacturer’s
responsibility to produce an MSDS and the employers
responsibility to communicate its contents to
employees.
Mechanical damage: in SPF-based roofing,
physical damage to a completed SPF-based roof system
not caused by normal wear and tear.
Mechanically fastened membranes: generally
used to describe membranes that have been attached
at defined intervals to the substrate. Membrane: a flexible or semi-flexible roof covering or waterproofing whose primary function is to exclude water.
Metal:
any of various opaque, fusible, ductile and
typically lustrous substances that are good
conductors of electricity and heat.
Metallic waterproofing: consist of finely
graded iron particles combined with an oxidizing
catalyst. When mixed with water (or water, cement,
and sand), the finely distributed particles expand,
creating a waterproof layer that becomes a part of
the surface to which it is applied.
Metal rain collar: a metal counterflashing
used to wrap a penetration and prevent water
infiltration though the top of the penetration base
flashing.
Meter: unit of length measurement in the
metric system; 1 meter is equal to 39.37 inches.
Metal roof panel: an interlocking metal sheet
having a minimum installed weather exposure of 3
square feet |